For sale: the demo album Ed Sheeran really doesn't want us to hear

The 29-year-old singer, who is now one of the world's biggest pop acts, recorded "Spinning Man" in 2004 at the age of 13, after experiencing his first heartbreak.

Opening up about the demo in his 2014 book "Ed Sheeran: A Visual Journey," he revealed that 19 of the 20 copies he made were in his possession and confessed he did not want anyone else to get their hands on a copy.

"There are probably 20 copies of 'Spinning Man' in existence, and I have 19 of them. I don't want anyone else to get hold of a copy!" he wrote "Most of the songs were about a girl called Claire. She was my first love when I was 13."

He continued: "She was my first love when I was 13. It was a very innocent love, and we only ever held hands, but it lasted a fair amount of time. Then came my first devastating break-up.

"Looking back, it really wasn't that bad, but at the time it was soul-shattering. When she left me, I wrote a lot of songs off the back of it -- my first love songs."

"Spinning Man" features 14 tracks with titles that sum up his teenage angst, including "Misery," On My Mind" and (oh, bless him!) "Moody Ballad of Ed."

A photo issued by British music memorabilia auction house Omega Auctions shows a teenage Sheeran strumming a guitar.

According to the listing, Sheeran gave the CD to a family friend in 2009 during his busking days and it is being sold by a relative of the friend.

The unearthed album is expected to fetch up to £10,000 ($13,108) when it goes under the hammer next month.

Although Sheeran didn't taste any chart success with "Spinning Man," three of his later albums -- "+" (Plus) , "x" (Multiply) and "÷" (Divide) -- were all released to critical acclaim.

At the 2016 Grammy awards he won Song of The Year and Best Pop Solo Performance for "Thinking Out Loud," which featured on "x." Two years later, "÷" took the Grammy for Best Pop Vocal Album. A single from the album, "Shape Of You," scored Best Pop Vocal Performance.